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Quantum decoherence is the effect that bridges quantum physics to well-understood classical physics. As such, it plays a crucial role in understanding the mysterious nature of quantum physics. Quantum decoherence is also a source of quantum…

Quantum Physics · Physics 2025-05-09 Jun Nishimura , Hiromasa Watanabe

We present an open loop (bang-bang) scheme to control decoherence in a generic one-qubit quantum gate and implement it in a realistic simulation. The system is consistently described within the spin-boson model, with interactions accounting…

Quantum Physics · Physics 2009-11-07 V. Protopopescu , R. Perez , C. D'Helon , J. Schmulen

We analyze a toy model that obeys environmentally induced decoherence and quantum Darwinism and satisfies the decoherent histories criterion and Leggett-Garg inequalities with respect to the pointer basis. Yet, the resulting "classical"…

Quantum Physics · Physics 2025-11-20 Irene Valladares Duque , Philipp Strasberg

In loop quantum gravity, the area element of embedded spatial surfaces is given by a well-defined operator. We further characterize the quantized geometry of such surfaces by proposing definitions for operators quantizing scalar curvature…

General Relativity and Quantum Cosmology · Physics 2018-09-26 David Grüber , Hanno Sahlmann , Thomas Zilker

Since inflationary perturbations must generically couple to all degrees of freedom present in the early Universe, it is more realistic to view these fluctuations as an open quantum system interacting with an environment. Then, on very…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-10 Jerome Martin , Vincent Vennin

Decoherence is the process by which quantum systems interact and become correlated with their external environments; quantum trajectories are a powerful technique by which decohering systems can be resolved into stochastic evolutions,…

Quantum Physics · Physics 2018-03-28 Todd A. Brun

We present a rigorous analysis of the phenomenon of decoherence for general N-level systems coupled to reservoirs of free massless bosonic fields. We apply our general results to the specific case of the qubit. Our approach does not involve…

Quantum Physics · Physics 2015-06-26 M. Merkli , I. M. Sigal , G. P. Berman

We analyze a system consisting of an oscillator coupled to a field. With the field traced out as an environment, the oscillator loses coherence on a very short {\it decoherence timescale}; but, on a much longer {\it relaxation timescale},…

General Relativity and Quantum Cosmology · Physics 2011-08-04 J. R. Anglin , R. Laflamme , W. H. Zurek , J. P. Paz

The so-called classical limit of quantum mechanics is generally studied in terms of the decoherence of the state operator that characterizes a system. This is not the only possible approach to decoherence. In previous works we have…

Quantum Physics · Physics 2015-05-18 Sebastian Fortin , Leonardo Vanni

An inhomogeneous (1+1)-dimensional model of the quantum gravity is considered. It is found, that this model corresponds to a string propagating against some curved background space. The quantization scheme including the Wheeler-DeWitt…

General Relativity and Quantum Cosmology · Physics 2015-05-28 S. L. Cherkas , V. L. Kalashnikov

Decoherence is an essential mechanism that defines the boundary between classical and quantum behaviours, while imposing technological bounds for quantum devices. Little is known about quantum coherence of mechanical systems, as opposed to…

Mesoscale and Nanoscale Physics · Physics 2017-10-26 Olivier Maillet , Frantisek Vavrek , Andrew D. Fefferman , Olivier Bourgeois , Eddy Collin

This article, as the first of three, aims at establishing the (time-dependent) Born-Oppenheimer approximation, in the sense of space adiabatic perturbation theory, for quantum systems constructed by techniques of the loop quantum gravity…

Mathematical Physics · Physics 2016-07-27 Alexander Stottmeister , Thomas Thiemann

We study the decoherence properties of a certain class of Markovian quantum open systems from both the Decohering Histories and Environment Induced Superselection paradigms. The class studied includes many familiar quantum optical cases.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. Twamley

The combinatorial problem of counting the black hole quantum states within the Isolated Horizon framework in Loop Quantum Gravity is analyzed. A qualitative understanding of the origin of the band structure shown by the degeneracy spectrum,…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Ivan Agullo , Jacobo Diaz-Polo , Enrique Fernandez-Borja

We review some approaches to the Hamiltonian dynamics of (loop) quantum gravity, the main issues being the regularization of the Hamiltonian and the continuum limit. First, Thiemann's definition of the quantum Hamiltonian is presented, and…

General Relativity and Quantum Cosmology · Physics 2012-03-08 Valentin Bonzom , Alok Laddha

We discuss the various manifestations of quantum decoherence in the forms of dephasing, entanglement with the environment, and revelation of "which-path" information. As a specific example, we consider an electron interference experiment.…

Quantum Physics · Physics 2015-05-13 Jen-Tsung Hsiang , L. H. Ford

The problem of topology change transitions in quantum gravity is discussed. We argue that the contribution of the Giddings-Strominger wormhole to the Euclidean path integral is pure imaginary. This is checked by two techniques: by the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 V. A. Rubakov , O. Yu. Shvedov

In this article, we study the problem of designing a Decoherence Control for quantum systems with the help of a scalable ancillary quantum control and techniques from geometric control theory, in order to successfully and completely…

Quantum Physics · Physics 2015-03-14 Narayan Ganesan , Tzyh-Jong Tarn

We study quantum decoherence of curvature perturbations at superhorizon scales caused by the gravitational nonlinearities. We show that cubic gravitational couplings, constrained by the spatial diffeomorphism invariance, lead to infrared…

High Energy Physics - Theory · Physics 2025-07-22 Fumiya Sano , Junsei Tokuda

An examination of the concept of using classical degrees of freedom to drive the evolution of quantum computers is given. Specifically, when externally generated, coherent states of the electromagnetic field are used to drive transitions…

Quantum Physics · Physics 2009-10-31 Jeff P. Barnes , Warren S. Warren
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